INFECTIVE ENDOCARDITIS, THE GREAT IMITATOR

Infective endocarditis (IE) is a devastating disease that, when not properly treated, progresses inexorably to death. Even with adequate treatment, lethality remains very high, around 20% in-hospital mortality, and in some Brazilian centers it reaches 41.3%. Over recent decades, there has been a significant increase not only in lethality but also in incidence. Its importance is further underscored by its ability to present in a wide variety of forms, making it crucial that physicians from multiple specialties be familiar with it. Its clinical diversity is such that it has been compared to syphilis and called the “great imitator”. Even so, the medical literature is extremely sparse in addressing this characteristic of IE. The objective of this study is to describe the diagnostic hypotheses at admission in patients who were ultimately diagnosed with definite IE in a reference hospital. From January 2004 to December 2024, there were 176 episodes of definite IE in 165 patients over 18 years of age, admitted via spontaneous demand to a university hospital. In 71 of these 176 episodes, the diagnosis of IE was already considered at admission, while in the remaining 105 cases, other diagnoses were initially proposed. Among the alternative diagnostic hypotheses, the most frequent were: fever of unknown origin (22), bloodstream infection (15), respiratory infection (14), heart failure (13), tuberculosis (13), urinary tract infection (10), anemia of unknown cause (9), others. When outcomes were analyzed, no significant difference was observed between patients whose initial diagnostic hypothesis included IE and those in whom only other diagnoses were considered, although there was a trend toward higher mortality in the latter group. IE can mimic numerous other diseases, and although the group of patients in whom IE was considered as an initial diagnostic hypothesis did not show higher in-hospital mortality compared to those in whom it was not initially suspected, there was a trend toward such an association.